* {
    margin: 0;
    padding: 0;
    list-style: none;
    box-sizing: border-box;
}

.clear {
    content: '';
    display: block;
    clear: both;
}

.left {
    float: left;
}

.right {
    float: right;
}

.wrap {
    width: 990px;
    margin: 0 auto;
}

header {
    width: 1200px;
    margin: 0 auto;
    height: 35px;
    background-color: rgb(245, 245, 245);
}